What is Molecularity?
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What is Molecularity?
From what I understand it’s just the number of reactants forming to a product. But I don’t think we went over moleuclarity as it applies to intermediate products. How would we calculate that?
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Re: What is Molecularity?
More specifically, molecularity is the number of species that must collide for a step in the chemical reaction to proceed, not just the total amount of reactants forming a product. This tells us the rate of a step in a chemical reaction. or using the rate of the step in the reaction, we can find the molecularity.
For example, given the rate of the reaction is k[A], the molecularity is unimolecular, or if the rate is k[A]^2, that step must be bimolecular.
Hope that makes sense
For example, given the rate of the reaction is k[A], the molecularity is unimolecular, or if the rate is k[A]^2, that step must be bimolecular.
Hope that makes sense
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Re: What is Molecularity?
You can also think about molecularity in regards to the order of a reaction, as first order is unimolecular, second order is bimolecular, and third order is termolecular.
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Re: What is Molecularity?
Molecularity is the number of species/molecules that react in an elementary step. A unimolecular reaction (k[A]) involves 1 molecule (that reacts with the solution, container walls, photons, etc). A bimolecular reaction (k[A]2) involves 2 species/molecules colliding.
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Re: What is Molecularity?
Also, the greater the molecularity, the less likely the reaction is to happen since the probability of that many molecules colliding is less.
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Re: What is Molecularity?
I don't think that molecularity isn't involved in intermediates. Molecularity only applies to the reactants in the rate determining step. If there are intermediates in the slow step, you have to solve for correct pre-equilibrium rate law, I believe.
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Re: What is Molecularity?
Here is a good video on the topic. It explicitly explains the difference between order and molecularity: https://youtu.be/qpoAb8rhUr0
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Re: What is Molecularity?
In lecture, Lavelle defined molecularity as the number of species in an elementary step. Molecularity of a reaction can be determined by the number of reactants (unimolecular, bimolecular, and termolecular.
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Re: What is Molecularity?
Elementary rxns are classified according to their molecularity, the number of reactant molecules, atoms, or ions taking part in that particular rxn
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